Database « Cache « JPA Q&A





1. first level hibernate cache , modify record directly at DB    stackoverflow.com

for first level of cache, what i understand is when we do saveorupdate , we need to call flush() to refresh the cache in order for subsequent select query from DB. ...

2. Knowing when hitting database vs cache    stackoverflow.com

Given all the smarts around Hibernate and it's various caching strategies, how do I know if a certain operation is resulting in a physical database hit, or coming from the cache? ...

3. Second level cache for java web app and its alternatives    stackoverflow.com

Between the transitions of the web app I use a Session object to save my objects in. I've heard there's a program called memcached but there's no compiled version of it on ...

4. Hibernate database integrity with multiple java applications    stackoverflow.com

We have 2 java web apps both are read/write and 3 standalone java read/write applications (one loads questions via email, one processes an xml feed, one sends email to subscribers) all ...

5. Why use your application-level cache if database already provides caching?    stackoverflow.com

Modern database provide caching support. Most of the ORM frameworks cache retrieved data too. Why this duplication is necessary?

6. Hibernate or browser caching DB results?    coderanch.com

I have a situation where I check to see if the user's login is still valid. This check is a simple database check of a date field. What I'm noticing is that if I change the value in the database, the hibernate code doesn't always "see" the new value and says that the user's account has expired when, in fact, I ...

7. Multiple Database configurations with Hibernate and caching    coderanch.com

Hi, I am building an webservice app which has 2 different DBs( Oracle and DB2). Please let me know whats the best way of designing the hibernate layer to access both the DBs ; I have some cross reference tables in both of them. I am planning to create a logical model of the physical DB model ( combining both Oracle ...

8. Question about cache and Transction sent to DB.    forum.hibernate.org

Using Hibernate maven artifact: org.hibernate hibernate 3.2.6.ga So I got caching working fine, the question is... Why is hibernate sending a BEGIN TRANSACTION/END TRANSACTION to the DB if the read data is coming from the cache. I traced SQL and I can clearly see that the cache is kicking in since there are no SELECT or other statements sent ...

9. cache problem with multiple database    forum.hibernate.org

hi every body i got a problem with hibernate cache im using hibernate 2.1 with ehcache and jboss 3.2.3 is there any solution to use one cache instance by session factory instead of unique cache for all session factory ? because the same mapping object is used in different database with auto increment id. ps : i dont want to modify ...





10. Manipulating Database Outside Hibernate And Caching Problem    forum.hibernate.org

Read through the forums and found a bunch of places saying that: 1. You cannot disable the second level cache by excluding it from the hibernate.cfg.xml, Hibernate will use EHCache by default. 2. If you manage your Sessions correctly and flush, close, and disconnect them at the appropriate times, you won't run into any problems with the session level cache. 3. ...

11. Problem syncing with database. Caching?    forum.hibernate.org

I have a basic Parent one to many Child relatonship. I am running my application from a servlet, with a ProposalManager which accesses my dao's. Here is my Proposal.hbm.xml: Code:

12. Comparing database copy with cached copy    forum.hibernate.org

Hi, 1. I get an object from the DB. 2. I change the data in a couple of fields in the object. Is there any way for me to compare data in 1 to data in 2. I tried doing a session.load(this.clazz, id); But, this gives me the data in 2, not the data 1. V

13. Architecture question synchronising database and cache    forum.hibernate.org

decairn wrote: It only actually matters at the point of commit(), so this looks like a versioning question more than a caching one. You can add exceptions handling if the db version is newer than the local session copy. Online docs have some information on how to integrate external applications, and a blog entry has some ideas too ( http://blog.hibernate.org/cgi-bin/blosx ... ...

14. multiple DB's and ehcache.    forum.hibernate.org

15. Caching & structures duplication over databases    forum.hibernate.org

Hibernate 2.1.6 Ehcache config activated in hbm files Progress 9.1E Problem synopsis: The appplication uses several databases while some of them use the same structures (classes). Saying Db1 with a class A - table t1 Db2 with a class A - table t1 With one row in db1 - t1 - key1 val1 db2 - t1 - key1 - val2 Using ...

16. Cache - Unable to see changes to DB    forum.hibernate.org

Hi sreerc, First of all, are you sure changes have been actually done to the database? If you enable show_sql property, when you commit your Transaction, does it perform an sql udpdate or insert? In case it does: I had a similar problem and I found out that sometimes it is better to close the session and open a new one ...





17. Session cache is not consistent with database ?    forum.hibernate.org

Take a look at the following sample code: 1 Configuration config = new Configuration(); 2 SessionFactory sessionFactory = null; 3 Session session = null; 4 5 try { 6 sessionFactory = config. configure() 7 .buildSessionFactory(); 8 session = sessionFactory.openSession(); 9 Transaction transaction = session.beginTransaction(); 10 Employee employee = new Employee(); 11 employee.setEmpno(new Integer(1)); 12 employee.setName("tanaka"); 13 employee.setAge(new Integer(25)); 14 session.save(employee); // ...

18. My Cache Does Not Reflect What Is In The Database.    forum.hibernate.org

So you're saying I need to use a Transaction object and perform a commit before the parent object will reflect the fact that I have added child records, right? Currently I am not using a Transaction object but I could change my code to utilize one. I thought a Session.saveOrUpdate() and then a Session.flush() would take care of that. If performance ...

19. Cache or Database    forum.hibernate.org

If it's just for debugging purposes, then you can get a handle to your CacheManager using CacheManager.getInstance(), then loop through the caches in there, checking for your object. If you want to run custom code based on whether or not an object is being loaded from the DB, then you probably want to put that code in an interceptor or a ...

21. second level cache and database timestamps    forum.hibernate.org

Hibernate version: 3.2 Name and version of the database you are using: mysql 5.x I've got the second level cache enabled, and when I update a row in the database, the "lastModifiedColumn" of that row is automatically updated (it's defined as a timestamp in mysql). However, Hibernate, b/c of the second level cache, doesn't seem to notice this. That is, the ...

22. Question about cache v.s database reads    forum.hibernate.org

Step 1. ---------- Subject object is being read from DB and your first level session is getting populated with this object. Step 2. --------- Since you are changing the one attribute in the object, the value present in the session is also getting updated. Step 3. ---------- This would merge your value from DB with the session and return the same ...

23. Hibernate is Hitting DB instead of Second-level cache    forum.hibernate.org

Hi , i was trying to test whether the data is retrieved from second level cache . I have to sessions s1 and s2. s1 is loaded an object with key. now i am trying to load the object with same key from using the other session s2 , according to my expectation the object is already there in second-level cache ...

24. JPA level 2 cache and external database modifications    forum.hibernate.org

Hi, I plan to use Hibernate with JPA API inside an EJB container with a level 2 cache. I'd like to modify database with native sql statements or use triggers that modify data or delete rows. I understand that the level 2 cache doesn't handle modifications that are done out of the scope of the entity manager and doesn't update the ...